This activity is aimed at the analysis and development of algorithms for the solution of very large linear systems (i.e., 10,000 equations and 10,000 variables). These problems are often associated to queue problems or arise in the discretization of infinite domain differential equations. A second topic concerns the study of iterative methods for ill-conditioned problems, like in some problems of image reconstruction. A third reseach activity concerns the analysis of the stability properties of “fast” methods for the solution of structured linear systems.